1. Field of the Invention
The present invention relates to a stator assembly of a motor.
2. Description of the Related Art
Conventionally, a laminated core, which is composed of a plurality of silicon steel sheet pieces punched out in a predetermined shape and stacked in layers, is widely used in a stator assembly for a motor. An electrical insulation coating is previously applied to the surface of a material sheet of which the silicon steel sheet pieces to constitute the laminated core are punched out, but since no such coating is provided on the cut surface of the silicon steel sheet pieces or the insulation coating previously applied is removed at the edge portion thereof, the laminated core generally is covered with an insulator made of an insulating material such as synthetic resin thereby covering the edge portion of the laminated core (refer to, for example, Japanese Patent Application Laid-Open No. 2006-129590 ([0029], FIG. 3)).
In the stator assembly structured as described above, since the insulator is of a two-part structure divided into two segments and is attached onto the laminated core such that one segment is fitted from one axial end side of the laminated core and the other segment is fitted from the other axial end side thereof so as to axially sandwich the laminated core, the axial dimension of the stator assembly increases by the aggregate thickness of the two segments of the insulator. Also, the two-part insulator hampers cost reduction.
In order to overcome the problems described above, a stator assembly is disclosed which includes a one-part insulator fitted onto a laminated core from only one axial end side of the laminated core (refer to, for example, Japanese Patent Application Laid-Open No. 2003-23743 ([0019], FIG. 1)).
In the case of the above-described one-part insulator fitted onto the laminated core from only one axial end side of the laminated core, one end of the insulator remains open, and therefore it is advisable that the insulator and the laminated core be so dimensioned as to provide a snap-fit condition therebetween for a secure attachment. This, however, results in that the surfaces of cover walls of the insulator are possibly scraped by the edges of salient poles of the laminated core when the insulator is snap-fitted onto the laminated core from the one axial end side of the laminated core, and thus the snap-fit condition of the insulator on the laminated core is deteriorated with scraped chips.